The invention resides in a pneumatic damper for slowing down movable furniture parts, including a cylinder and a piston which is axially movably supported in the cylinder and connected to a piston rod subjected to internal and external forces. The piston includes a seal element acting also as a check valve and divides the cylinder into a vacuum chamber and a compression chamber from which gas can released depending on the direction of a piston stroke. The piston has seal elements which are in contact with the cylinder walls at least in an end position of the piston where it is not subjected to gas pressure. The cross-section of the interior of the cylinder becomes larger at least in parts thereof in a uniform way toward one end position of the piston and the piston is provided with at least one sleeve-like seal element and is disposed in close contact with the cylinder walls at least in the area thereof adjacent the piston rod.
Such a device is disclosed in U.S. Ser. No. 11/168,035 where it is part of a guide system. However the cylinder piston unit disclosed therein operates in the slow-down stroke only against a pressurized air cushion.
EP 1 260 159 A2 discloses another movement damper in which the slow-down forces are generated by compression and vacuum forces. However, with the arrangements described, only a relatively small vacuum can be generated. Furthermore, during the slow-down stroke, the force generated by the vacuum is effective only relatively slowly.
It is therefore the object of the present invention to provide a pneumatic retarding or damper mechanism wherein a retarding effect is rapidly established and wherein the damper is stopped in the end position thereof without a hard impact and without rebound and which furthermore requires only a relatively small amount of space.